week 9: mutation, dna repair and variant discovery

Question 1

define:
- germline vs somatic
-spontaneous vs induced
-mutation vs polymorphism

Answer 1

• happens in gametes vs happens in body cells
  -errors during cellular processes vs from mutagens
  -present in less than 1% vs more than 1%, already established variations

Question 2

purine v pyrimidine bases

Answer 2

purine A,G
pyrimidine C,T

Question 3

point mutation types

Answer 3

• substitution (incl. transition:purine->purine;transversion:purine<->pyrimidine)
• insertion
• deletion

Question 4

chromosomal mutation types

Answer 4

• inversion: a segment is flipped. effects depend on breakpoint and position effects
• deletion: can be serious
• duplication: not detrimental
• translocation: a segment of chromosome attaches to another. can be reciprocal and non-reciprocal

Question 5

impacts of mutation

Answer 5

• silent: AA doesn’t change
• non-sense: AA changes to stop codon (UAA, UAG, UGA)
• frameshift: deletion/insertion of bases that is NOT a multiple of 3.
• missense/conservative - AA changes to another AA with similar properties. minimal loss of function.
• missense/non-conservative - AA to another AA, which is different from it. Affects protein function.

Question 6

examples of mutagens

Answer 6

• biological: some biological agents like HPV (virus)
• physical: non-ionising radiation (UV, EM) and ionising (X, gamma)
• chemical: changes properties of nucleotides so it incorporates the incorrect base